Process for the production of alkylene glycols with metalate-containing solids

Abstract

An improved process for the hydrolysis of alkylene oxide to produce alkylene glycol which comprises: (a) reacting alkylene oxide and water in the presence of a selectivity-enhancing metalate-containing solid until about 90-95% of the alkylene oxide is converted to alkylene glycol; and (b) completing the hydrolysis reaction of (a) in the absence of the selectivity-enhancing metalate-containing solid.

What is claimed is: 
     
       1. A process for the hydrolysis of alkylene oxide to produce alkylene glycol which comprises: (a) reacting the alkylene oxide and water in the presence of a selectivity-enhancing amount of a selectivity-enhancing metalate containing solid, until about 90 percent to about 95 percent of the alkylene oxide is converted to alkylene glycol; and   (b) completing the hydrolysis reaction of (a) in the absence of the selectivity-enhancing metalate-containing solid.   
     
     
       2. A process as recited in claim 1 wherein step (a) is conducted until about 93 percent to about 94 percent of the alkylene oxide is converted to alkylene glycol. 
     
     
       3. A process as recited in claim 1 wherein the alkylene oxide is ethylene oxide. 
     
     
       4. A process as recited in claim 3 wherein the alkylene glycol is monoethylene glycol. 
     
     
       5. A process as recited in claim 1 wherein the metalate anion in the metalate-containing solid is represented by the formula:   [(A).sub.m M(O)].sup.-q     wherein M is a polyvalent metal atom having a positive functional oxidation state, q is the negative charge of the metalate anion, and A is one or more substituents to fill the remaining valencies (m) of M and is selected from the group consisting of double bonded oxygen and --O-- wherein at least one A is --O--.   
     
     
       6. A process as recited in claim 5 wherein the electropositive complexing sites in the metalate-containing solid are represented by the formula:   [--X--(R).sub.n ].sup.+     wherein X is nitrogen, phosphorous, sulfur, or arsenic bonded directly or indirectly to the support, each R may be the same or different and is hydrogen, monocyclic aryl or aralkyl of 6 to 8 carbon atoms, monocyclic aralkyl of 7 to 9 carbon atoms, or alkyl or alkoxy of 1 to about 6 carbon atoms and n designates that sufficient R groups are provided to satisfy the remaining valencies of X.   
     
     
       7. A process as recited in claim 6 wherein the metalate anion comprises at least one of molybdate, tungstate, metavanadate, hydrogen pyrovanadate, and pyrovanadate. 
     
     
       8. A process as recited in claim 7 wherein the solid support in the metalate-containing solid comprises an anion exchange resin. 
     
     
       9. A process as recited in claim 8 wherein the metalate-containing solid is a tungstate-exchanged anion exchange resin. 
     
     
       10. A process for the hydrolysis of alkylene oxide to produce alkylene glycol which comprises: (a) reacting alkylene oxide and water in the absence of a metalate-containing solid, until about 10 percent to about 35 percent of the alkylene oxide is converted to alkylene glycol;   (b) Continuing the hydrolysis reaction of (a) in the presence of a selectivity-enhancing amount of a selectivity enhancing metalate-containing solid, until about 90 to about 95 percent of the alkylene oxide is converted to alkylene glycol; and   (c) completing the hydrolysis reaction of (b) in the absence of the selectivity-enhancing metalate-containing solid.   
     
     
       11. A process as recited in claim 10 wherein step (a) is conducted until about 20 percent to about 30 percent of the alkylene oxide is converted to alkylene glycol. 
     
     
       12. A process as recited in claim 10 wherein step (a) is conducted until about 27 percent of the alkylene oxide is converted to alkylene glycol. 
     
     
       13. A process as recited in claim 10 wherein step (b) is conducted until about 93 to about 94 percent of the alkylene oxide is converted to alkylene glycol. 
     
     
       14. A process as recited in claim 10 wherein the alkylene oxide in ethylene oxide. 
     
     
       15. A process as recited in claim 10 wherein the alkylene glycol is monoethylene glycol. 
     
     
       16. A process as recited in claim 10 wherein the metalate anion in the metalate-containing solid is represented by the formula:   [(A).sub.m M(O)].sup.-q     wherein M is a polyvalent metal atom having a positive functional oxidation state, q is the negative charge of the metalate anion, and A is one or more substituents to fill the remaining valencies (m) of M and is selected from the group consisting of double bonded oxygen and --O-- wherein at least one A is --O--.   
     
     
       17. A process as recited in claim 16 wherein the electropositive complexing sites in the metalate-containing solid are represented by the formula:   [--X--(R).sub.n ].sup.+     wherein X is nitrogen, phosphorus, sulfur, or arsenic bonded directly or indirectly to the support, each R may be the same or different and is hydrogen, monocyclic aryl or aralkyl of 6 to 8 carbon atoms, monocyclic aralkyl to 7 to 9 carbon atoms, or alkyl or alkoxy of 1 to about 6 carbon atoms and n designates that sufficient R groups are provided to satisfy the remaining valencies of X.   
     
     
       18. A process as recited in claim 17 wherein the metalate anion comprises at least one of molybdate, tungstate, metavanadate, hydrogen pyrovanadate, and pyrovanadate. 
     
     
       19. A process as recited in claim 18 wherein the solid support in the metalate-containing solid comprises an anion exchange resin. 
     
     
       20. A process as recited in claim 10 wherein the metalate-containing solid is a tungstate-exchanged anion exchange resin.